There are no live-aboards operating out of Guam, nor in Yap. But there are a few operating in Palau. From what I've heard though, it is much better to dive Palau with the day boats:
1. all the boats go to the same spots, day boats and live-aboards
2. the boat ride out to the rock islands every morning is a fun time in itself, something you won't get with the live-aboards
3. if you really want to spend the night under the stars on the water, better to camp out on a rock island instead of cramped up on the boat. Sam's Tours rents camping equipment and can arrange to pick you up on your little island in the morning for diving.
4. It's nice to take a break on land during the late afternoon and evening... check out some local food, walk around the neighborhoods, check out the local bar, the gift shops, etc.
All in all, you will save a lot of money, Palau is one of those few destinations where its better to go with the day boats.