I know they will depend largely on the layout of the house, the existing plumbing, amongst other things.

Look for houses/townhouses with a "roommate" layout -- at least one bathroom per bedroom -- so shared areas are only kitchen, laundry and dr/lr.  2/2.5s are pretty easy to come by for relatively decent prices in Atlanta, or 3/2.5 (sometimes 3 full bath) townhomes are also plentiful. 

And you can apply this to just about anything; granite counter tops, odd layouts, bedroom and bath counts, etc. 

I only want to sell because it's layout lacks renting ability...or my imagination for renting it does anyway:)

Besides size other layout issues can impact value, like a bedroom on a floor without a bathroom.

Unless the house was larger than just about anything around there I'd think the units are tiny, and some may have wacky layouts. 

As long as the layouts are decent, the units have decent light, etc., they will probably get 1.6 on the open market; probably from someone that will live in the vacant unit.

I've only been looking in the Abilene market for about a year now but in my experience I would agree that the multi-families do sell quickly and because many of them have unconventional layouts, they can be difficult to finance.

Depending on the layout, I wonder if there is a company that does inpatient rehabilitation of some type that would be interested.

So I'd suggest before you jump into opening an LLC to speak with a REI savvy CPA, lay out your current situation and plans and see what he/she will suggest.