These are the icons extracted from my dll's... and about the ones I had trouble with, those are:
*
[...] when I get no signal, I get the activesync icon with little X under that[...] --->
phcanoverbmp_67.dll
*
[...]"searching signal" icon is like the one for "connecting wifi" (a rod with the 3 counting dots)[...] [...]nope they are just similar--->
phcanoverbmp_64.dll to 91 AND
shellres_4698 to 4721
* [...]I get the classical "greyed out" 3G signal with no active signal icons, are 22219, 22220, 22221 or 22222 in tapres.192.dll)
*
[...]And I often get, only in homescreen, shellres_8228.dll
for no reason, which disappear as soon as I enter "programs" or "settings" or launch any program.
*
[...]"wifi detected" is stock
Hope you can sort it out something useful!
EDIT: BTW, why do you say GSM signal icons/bars cannot be changed? I used tsowen's and misfortun's but I never had issues... or did I get it wrong?