As a US-passport holder who lives in SE Asia and travels frequently to Indonesia--
1) The added-pages option for US passports that was free of charge in 2009 when this thread was begun is no longer free. You can still add pages, but you have to pay a steep fee for this. You can add as many as 3 inserts total before you have to buy a whole new passport, regardless of whether you've reached the expiration date. My current passport has reached the limit of page additions (one TSA agent told me I had to put my "book" in the scanner as I held my passport to walk through the metal detector arch), and I expect to have to purchase a new passport before mine expires five years from now. Additional pages are available at any US Consulate ACS office if you find yourself in the middle of a trip without sufficient visa pages.
2) Indonesia is currently in the midst of moving from a full-page visa sticker to a half-page one. I've had both types very recently. It's possible that offices that still have a stock of the "old" full page visa stickers need to use this stock up before making the switch rather than just throwing the old ones away and using the new ones. I dunno. But I do know that I've received the full page ones in trips subsequent to times I've received the half-page ones. Regardless, you will need one full page for a visa sticker (in case you enter at a booth using the old full-page stickers) and another (partial) page for your in-stamp and your out-stamp. It's not necessary that these pages be contiguous. I don't have any visas/stamps in my own passport that are on contiguous pages, as a matter of fact. Furthermore, it doesn't matter at all what is printed on the top of the passport page. Any page will do, even the one that says "Endorsements" which is theoretically not intended for visas or visa stamps (this page contains notation of amendments to the passport such as the addition of pages).