Hi Tubbs
As far as uk brokers are concerned, it's been a while since I looked into this. Anyway the following may be of interest although it's possible things may be different now:
* Berkely futures, there minimum opening balance used to be around £7.5k
* ODL futures (not the spread betting part of their biz) no minimum opening balance as such, however you will have to deposit the initial margin of whatever you want to trade, plus around 25% or so of that figure
* Sucden financial, I think there opening balance is around £5.5k
* MF Global - £10k
Cheers
Peace