Might as well get on with something whilst you're waiting lol.

Regarding single channel ESC's I know that Nuts & Bots DO have some in stock but each will cost the same amount as a dual channel. The tradeoff is that single channel ESC's are able to supply much more power to your motors. Ranglebox (run by Ellis of Pulsar fame) sells Botbitz ESC's which are £30 each but wouldn't you know it he's out of stock too.

There's a big thread about Speed Controllers which could offer you some ideas as well as a few build diaries but other than that I don't have too many ideas I'm afraid.