I don't personally know any teams exclusively from warwickshire (even though I live there!) - But get yourself down to NPF Basset's Pole, that'll be your best bet.
I think the Sneaky Snorkels are down that way a fair bit... Find the guy with the scary amount of hair and you've found 'em
Like emisnug said, get over to NPF from Diamond Wars and join the USDE, we have a number of squads based around the midlands. Sneaky Snorkels, All Blacks and the Penetrators are all local.