Numerous 4 channel recorder options around these days. Choice partly depends on how many channels of P48 you want supplied by the recorder itself (ala a single all-in-one box), or if you plan to use an outboard preamp/phantom source.
As for 3 mic configs- Yeah do it! Three mic configs are powerful tools, generally unappreciated. I suggest turning the old school AUD Dead gun technique inside out with a single forward facing shotgun placed in the center between two omnis or cards spaced about twice as far apart as you'd do for 2-channel stereo. If you can't double the spacing (or more), are in a good location and the room is decent, rotate the cards 180 degrees apart to face fully to either side, which maximizes their the level differences to help compensate for reduced timing differences due to a less than optimal spacing.