Excuse my naive non Android ROM/Rooting skills for a moment.
Just for example, if i have say a samsung galaxy s II, and i don't want touchwiz, is there just a generic Gingerbread ROM available to make the UI just like a Nexus S? Is this possible on any android device once you have it?
you can check the forums either here or on xda and see if anyone has made a ROM without or at least masks it. i know for my Atrix, i downloaded a ROM that masked the motoblur interface when i was on froyo.
A developer needs to put together a custom ROM for you to use. If one doesn't exists, then you are stuck with the ROM shipped with the phone. I would do as suggested above and check the rooting/development forums of AndroidCentral and XDA to see if something exists for your device.