This is just a follow-up my previous post on Scottrade enabling electronic deposits, but not withdrawals. You can get withdrawals too if you (a) can get $5,000 in total account equity (stock holdings + cash), and (b) use an online bank account that allows external links (ING, Emigrant, HSBC, etc.).
No tricks here, if you satisfy (a) Scottrade will give you checkwriting capability upon request. You can then either use the checks themselves or the account and routing numbers on them to link with other accounts. If you use a CashEdge-based system like with HSBC Direct, it’s even built in; Here’s a screenshot. They say that if you go below $5,000 later you may lose checkwriting privileges, but I’ve been under for about a month now with no consequences.