OK, here is an unverified thickness chart for Sprint/CDMA TouchPro 2 phones with extended battery packs added. If anyone has the data for GSM cases, please indicate if the thickness is any different.
_____OEM/__HTC(cdma)2150/Seidio(cdma)3500/Mugen(cdma)3200/Mugen(cdma)4500
mm:_17.3/__________20.25/_______20.3-21.3/________22.3mm/________30.3mm/
in:__.681/___________.797/__________.8-.84/___________.878/__________1.193/
The OEM thickness in MM comes from PDAnet. Conversion to Inches done by dividing by 25.4 [mm-inch].
The Seidio thickness is determined from their website claim to only add 3-4mm to the thickness. PEOPLE WITH THIS BATTERY: PLEASE VERIFY IT FOR US!
The Mugen numbers are VERY approximate, as they are based on my lame attempts at measuring the thickness of the OEM back and adjusting for the Mugen battery covers.
The Mugen 3200 cover is 15mm thick, or .6 inches. The Mugen 4500 cover is 23mm thick, or .9 inches.
All numbers for their thickness are thanks to NIKOLAI at Mugen.
I came up with an OEM battery cover thickness of 10mm.
PLEASE confirm this if you have better tools to measure than I do, and then modify the overall thickness accordingly.
The forumula I used was: [OEM overall thickness-10mm+Mugen thickness]
THANK YOU, Cyclonut, for contributing the HTC Extended thickness!