Op, those that you found - it says GC - they are usually taller than 10".
With 10" height limit you can fit 3 x 100 AH AGM like Universal, aka UPG:
http://www.wholesalesolar.com/products.folder/battery-folder/UPG.html. Shop around, there can be better prices than $187.
Or, with more cash - Lifeline 100 AH
http://www.lifelinebatteries.com/rvflyer.php?id=2 - I think they are around $300 a piece.
If you find Deka Gr27 under $200 a piece, this is a better brand than UPG, though not better than Lifeline. One problem is that Deka Gr 27 is 90 Ah, not 100 Ah. Which makes sense - Deka cost more per AH than UPG.
... concerned about off gassing just under the bed area
This means - get AGM.