I know exactlly what you mean, spaces is an idea candidate for 3/4 finger gestures but no, i havent found a way of customising this yet, and hope some customisation appears soon. I hardly ever use the 4 finger up to reveal the desktop so that could be better used to reveal spaces perhaps.
But it is a new feature, so from Apple's point of view, its probably better to start with no customisations and slowly introduce them than to have a fully configurable setup that is buggy