As long as you have an alternative to red stilettos when sewing most treadles should be a good candidate for your projects
Some say you can quilt on any machine, its' mostly about fine tuning and getting to know the machine. Some favor CB hook machines (or vertivally set bobbins) for freemotion work, like Singer model 15. There are a lot of variants on this particular feature, most of the old brands had derivatives of this type. Few older machines have stitch length lever with reverse, some did, but Singer didn't introduce on until around 1930 (1928). In general, these are very nice machines to work on, and are in general well worth fixing up for the jobs we do in 2018. Models with out reverse shouldn't be ignored, particularly if you keep a second machine with various more modern features.
My suggestion is take a look at any treadle in nice condition, they tend to be very capable machines. The long bobbin / shuttle models are up to the job, the trick with the bobbin is to wind a few in advance if you know you will use a lot of thread. There are various Rotary machines, Wheeler and Wilson No 9, Gritzner, Pfaffs, Singer,... As long as they are intact with bobbin case/shuttle and with a few accessories they can be ideal. If you fall for a machine you can most likely find parts for it, given time, patience and money anything can be done. Singers are easy, replacement parts are available from several sources.
I know some who have taken on an old Singer VS as a favorite, another has a Singer 28 as her best straight stitcher, others brag something awful of their W&W No 9,... I know someone who has a 1930s Vesta 302 zigzag in a treadle. I am very tempted to go hunt for one. I swear those Necchi BUs are well worth it too, they came both as treadle and electrical. I am fascinated by the early cast iron zigzaggers.