Marmot Trestles 20 Semi Rec Sleeping Bag: 20 Degree Spirafil - 2008 BCS

This bag has a length that extends from 6' to 6'6" depending on your size. That being said sleeping pads are all about your personal preference and comfort level. I prefer blow up pads from Therm-a-Rest. They compress and are rather easy to carry and inflate. Remember sleeping pads are made to approximately the same length and dimensions as standard sleeping bags.

Here are a couple of suggestions:
http://www.backcountry.com/outdoorgear/Therm-a-Rest-Trail-Sleeping-Pad/CAS0295M.html <--- Cheap, inflatable, and comfortable to me.
http://www.backcountry.com/outdoorgear/Big-Agnes-Air-Core-Sleeping-Pad/BAG0011M.html <--- By Big Agnes. A little more expensive, but you are more cushioned (in my opinion).

Marmot supplies a compression stuff sack with this bag. Here's more information:

http://marmot.com/products/trestles_20_semi_rec_reg?p=117,173

Yes, retangular liner is the way to go. You might have some extra fabric down by your feet, but if you use a mummy liner you lose any advantage to getting this semi-rectangular bag in the first place.

Yes same size and also keep in mind to be zip in compatible 1 bag needs to be left zip and the other bag a right zip.

I'm exactly 6' and I got a regular bag. You can stretch out some still, as the bag iteslf stretches some. Plus, you have less space to warm up with your body heat so you get warm faster.

The regular is also 1/4 lb lighter, though since it's a heavy bag, you probably aren't concerned about weight.

Stuff size 8.5 x 18inch for this exact bag... Love the bag btw.

Mark,I have the Trestles 15 long bag, and compressed in its sack it comes to 10" high by 9" wide or just larger than a basketball. This bag wieghs almost a full lb more and is a little bigger, so you can expect it to stuff larger.