been there...
You absolutely can get a worthy drum sound w/only four mics. Before I bought my V-drums and when we were limited on mixer space, I've used to use 3 and still got a nice, live full sound.
I'm going to echo Drummerbones' sugg about being VERY careful about getting enough toms in the mix (especially low toms--you don't want those to be thin in the mix). One recommendation may be that you dedicate one mic near the upper toms and one for the lower (of course positioning for enough cymbal bleed).
But take into consideration your brand/type of cymbals (are they heavy?/thin?/quick?/sustained?) and position relative to their demand, and the drummer's playing style. For recording, I even recommend *gasp* moving your pieces around to accomodate the recording as much as you possibly can.
Also, in regards to cymbals, sometimes dampening them has helped me get a better overall mix.
One last suggestion: think outside the norm with each unique situation.
I've postioned a mic up underneath the toms before because no matter where we placed the mics, the cymbals always seemed to be too loud in the mix.
And in one recording situation...in order to get a drum mix we liked, I actually was forced to dampened the cymbals to the point where they were still physically there to hit/play, but made almost no sound and the used ALL the mics to mic the snare/kick/toms exclusively. Then, overdubbed the cymbals in seperately on another stereo track (which turned out to be a bonus in that there was much better drum control during mixing!)
Try anything and everything at least once.
ub