The problem is that most manufacturers are focusing on their newer products. Wopad seems to have died off after releasing Wopad i7 and i8. I definitely did not count on them being so inactive in releasing updated firmware. At the moment, I will be avoiding Wopad for a long time. I may go with Aurora II or Onda. I still hope to get a 7" tablet instead of a bigger 8-10" one. I will keep a lookout for RK3066 and 8726-MX devices.The stock/customized 1.28 firmware from us was based off Rockchip's 1.28 SDK. Cube's K8GT 1.0x firmware is based off Rockchip's 2.1 SDK. ie, much newer, faster & better looking SDK. Still based on Gingerbread 2.3 but has better performance and uses Android 3 UI. Too bad I could not find a working SDK 2.1 firmware version with camera and HDMI though. That would have been perfect for our tablets.
P75HD is using AllWinner A10 ARM chip. This is only about 30% better than what you have now. Better to get tablet with either RK3066 or 8726-MX (AKA 8726-M6) which are 1.5GHz dual core CPUs + dual or quad core GPUs. Those are more powerful ARM chips and will give 250% or more performance to what you have today. RK3066 is better choice out of the two and one that I prefer but either one should be good to get.
Ainol Elf-II w/TFT screen (out now: $125 or less shipped) and Aurora-II w/IPS screen (out end of June: pre-order for $160 or less shipped) both use 8726-M6 chip. Only downside is that Flash in web browser, BBC iPlayer & Netflix may not work properly or well. Otherwise Youtube app and everything else will work really fast and great. Or wait 3-4 months for other companies, like Onda or Cube, to release 7" 8726-MX or RK3066 tablets. Cube may use RK3066 for 7" since that is what their 9.7 & 10.1" tablets are switching over to.