I picked up a couple of those Guillow's foam shuttles a few years back, and they're a blast. I epoxied a plywood hook into the nose of one, and piggyback it on my upscale (1.68x) Orbital Transport. It glides beautifully.
The second one, I fashioned some balsa elevons, embedded micro servos into the wings, and hollowed out the fuselage section to hold a Hitec 555 receiver and a 50mAh nicad battery pack. The one time that I flew it (at a NARHAMS launch) , the boost and separation went well but once I tried putting some control input into it, it went into a spiral dive. I released the controls and it resumed gliding (at a steep, fast angle) but there wasn't time to try another maneuver - it came in headed right for us, and bonked into Don Brown's truck (no damage to either). I haven't flown it since, but if I can find a lighter RX/battery pack combination, I intend to give it another go. It's just too heavy with the current RX/battery - it doesn't really fly so much as it falls... with style.