Well, just thought I'd report that my final decision was to... Do Nothing. None of the apps I looked at really have what I want. (Of course, lots of stuff for 12 year old wannabe rappers who don't know the first thing about music.) The gear I have now gets the job done - my goal was to simplify and consolidate. But the more I read, the more complicated it got. However, the three apps I auditioned WILL do something my keyboards and modules don't do: crash with irritating frequency. When the dance floor is packed and the drummer clicks off the next song, I can't be the guy who yells "Wait a minute" while I reboot. After that happened a few times, I'd be the guy who doesn't get called for the next gig... So it looks like, at least for me, the 21st Century hasn't quite arrived.

Anyway, here's what I came away with (keep in mind, I was looking specifically for keyboard modules to use on the fly with my 64Gb iPod Touch 4G during live gigs):

Garageband ($4.99 / 689.5 Mb)
(Numerous reviews, demos & tutorials online)
Inexpensive!!! and has some good keyboard sounds (MUCH better than the ones on my OSX version) and has a sampling feature for creating your own patches. But you have to maneuver around all the other B.S. to get to them. Drum machine, sequencer, recording studio... It's trying to be all things to all people.
DaleMac's Rating: Close but no banana

SampleTank ($19.99 / 1.03 Gb; piano expansion pack $9.99; e.piano expansion pack $4.99)
Review: http://appcrawlr.com/ios/sampletank
(MANY demos on YouTube)
Has the best-sounding selection of keyboard voices. I discovered the reason the Free version is so huge: all the voices are already installed but you have to buy the expansions to unlock them. Takes forever to load. And, again, too many extraneous features to get around. Control buttons are too small on iPod - hit the wrong one(s) and you get lost, or crash.
DaleMac's Rating: One middle finger for no "Lite" version (and for clicking the "Remove" button)

iGrand ($19.99 / 256 Mb; expansion pack $9.99)
Demo: http://www.youtube.com/watch?v=VPrK_mkRrbg
By far the easiest to use with its scrolling piano selector, although the "control knobs" are somewhat awkward. True, it doesn't come with all the useless extra functions, but it has no electric pianos or organs. If and when they make a version of iLectric for iPod, I'll have to switch back and forth between apps to access them, no thank you.
DaleMac's Rating: One outstretched arm as I sadly wave buh-bye

============================================

And in case any members are interested, here are a few of the links I visited, although most of this information may be obsolete before you can blink an eye.

CMP Grand Piano for iPad iPhone 1GB piano
http://www.crudebyte.com/mobile/cmp_grand_piano/
http://www.youtube.com/watch?v=zoNT8IVrXeE

WaveSynth
http://www.crimsontech.jp/eng/wavesynth/iphone.html

8 Piano Apps Tested
http://www.youtube.com/watch?v=LRnkbLCu1o0

Misc. links about apps:
http://appfinder.lisisoft.com/tag/mi...nd-module.html
http://www.iosmusician.com/app-lists/core-midi
http://appcrawlr.com/ios-apps/best-apps-sound-modules
http://www.kvraudio.com/forum/viewtopic.php?p=4782769

Midi Connectors/Accessories:

IK Multimedia iRig MIDI
Review: http://www.ilounge.com/index.php/rev...etank-for-ios/
IK Multimedia iRig Midi prices:
Website: http://www.ikmultimedia.com/products/irigmidi/
$69.99 includes "SampleTank FREE" for iOS
http://www.amazon.com/IK-Multimedia-...=cm_cr_pr_pb_t
http://www.amazon.com/IK-Multimedia-...ef=pd_sim_MI_3
$50.59 free shipping
http://www.rakuten.com/prod/ik-multi...230241482.html
$64.00 free shipping
http://www.sweetwater.com/store/detail/iRigMIDI/
http://www.guitarcenter.com/IK-Multi...64-i2120613.gc
$69.00
http://www.samash.com/ik-multimedia-...ipad-iirigmidi
http://www.uniquesquared.com/ik-mult...s-devices.html
$69.99

Line 6 MIDI Mobilizer II
Review: http://createdigitalmusic.com/2010/1...ich-apps-work/
Line 6 MIDI Mobilizer II prices:
Website: http://line6.com/midimobilizer/mmii/
http://www.sweetwater.com/store/detail/MidiMobil2
$69.95
http://www.guitarcenter.com/Line-6-M...20-i2244813.gc
$69.99 (online only)
http://www.samash.com/line-6-midi-mo...ipad-lmidimob2
$69.99

Misc. links about accessories:
Connecting a USB MIDI Controller or Audio Interface to your iPad using the Camera Connection Kit
http://www.youtube.com/watch?v=xZOdtZ92iwQ

Lightning to 30-pin Adapter $29.99
http://store.apple.com/us/product/MD...apter?fnode=3a
Apple iPad Camera Connection Kit $29.99
http://store.apple.com/us/product/MC...connection-kit
Apple iPad Camera Connection Kit (MC531ZM/A) $25.49 free shipping
http://www.amazon.com/gp/product/B003K1EYM6/

i-MX1 $69.99
http://usa.yamaha.com/products/music...sb-midi/i-mx1/

iConnectMIDI-1 $79.99
http://www.iconnectivity.com/iConnectMIDI1

MIDIConnect $39.99
http://store.griffintechnology.com/m...rface-for-ipad

MIDI Keyboard Connections information
http://www.claviercompanion.com/conn...yboard-to-ipad

iPhone Jailbreak Tweak For iPad Camera Connection Kit Support, iPhone USB MIDI
http://www.synthtopia.com/content/20...hone-usb-midi/