Sending out an SOS

Okay, lurker parents. I need advice.

Bit of background: Rocco has always been a picky sleeper. He's noise-sensitive, position-sensitive, just generally a SNAG (sensitive new age guy). About a month ago, we finally bought Healthy Sleep Habits, Happy Child and it worked for us. After two days, Rocco was on a better nap schedule at home (read: one where he napped) and was sleeping better at night. He has always woken up once during the night to eat, but now he goes (oops, went) right back to sleep after. I've been okay with the once-a-night feeding, although DT and I did just start talking about trying to eliminate it. (Side note - our pediatrician accused me (nicely) of spoiling him, which is approximately the first time anyone has ever accused me of that.)

Last night, we had our typical bedtime routine, culminating with me nursing Rocco, then putting him in his crib. He fussed a bit as I went to the door (normal), then stopped as I closed the door (normal). About two minutes later, he started - hmm, what is the word? - squealing, shrieking, screaming, none of those really do it justice. It was an unusual timbre for his vocalizations, so I went in and found him standing up in the crib. He's been pulling up, but hasn't really tried sitting down yet, so it's fair to say he was stuck. I lay laid placed him in a supine position and left again. Lather, rinse, repeat. We did this three times within the space of a few minutes, at which point I stopped going in, because clearly my options were:

1. Get carpal tunnel from repeating the drill a hundred times over the next hour or
   
2. Let Rocco figure out what to do.

Bad mother that I am, I chose option 2. It took 45 excruciating minutes, but he finally got himself back down somehow and went to sleep.

All was well until he woke up at 4:30 for his usual feeding. He was just cooing a bit, not crying, but when I went in, yes, he was standing up again. No problems after the feeding, but then at 5:45 (NOT our typical hour to wake up), he was up, screaming, standing, again. After 30 minutes, when it became clear that he was too well-rested to feel motivated to solve his problem, DT went to get him out of the crib.

I don't think we ran into this with WonderGirl. Her height:coordination ratio was different from Rocco's, and I don't think she was tall enough to pull up in her crib before she had figured out how to sit down again. So, once again, we run into a situation where Rocco might as well be our first child for the amount of useful experience we have.

Any suggestions? I hate to leave him there standing up and crying, but I also know him and know that if I keep going in, we could continue this forever. It's just his nature. This is complicated by the fact that we'll have houseguests for several days, so starting tomorrow night, DT and I will be sleeping in Rocco's room. I can just see him standing there, watching us, waiting for rescue. So, when you give me expert advice, please include something that will work, oh, I don't know, immediately.

Thanks so much.