Hi gbaman, Unfortunately there are several builds for the Excel and they are currently selling with ICS allready installed now too.
I thought that the later Excels had 512Mb but you say yours only has 256 Mb so you may have one of the earlier or even original build models. Look in system settings/about tablet and post your build back here, that may help.
Meantime, if you are quite happy to flash the Excel 4.0.4 rom and uderstand exactly what you need to do if you want to change it back later - then it is your choice. I am running an original build Excel with Suggsy's 4.0.3 ICS rom and it is so much better than 2.3.4.
I haven't tried the 4.0.4 rom yet as I have only recently put the 4.0.3 on and I am very happy with it so far.
I don't know that any of the roms support blue tooth dongles yet but perhaps someone else can help you with that.