one of the smaller Domke bags. I have just bought a F6 for a three body M kit and it is perfect, so something smaller would be just the ticket. Padded enough, but far more spacious than the over padded bags that are so ubiquitous. Low key (the olive ones look like army surplus bags). Got the F2 as well for when carying my mamiya 7 outfit. V happy.
Personally, with a body and two lenses, I normally sling the camera under my coat with a smooth leather strap and put the spare lenses in pockets or canvas military belt pouches (v small ones). I sometimes use one of the small Leica Billinghams. The Billingham has a much 'posher' build than the Domkes, but the latter seem more than solid enough. The only issue is with the plastic strap sliders, although one must remember that such things are used on backpacks for military use and they don't generally break unless tensioned in the wrong way (or trodden on/driven over). I think they will be fine. The canvas feels very tough and I can confirm that they are waterproof enough after having mine covered in rain and sleet a couple of times. The internal compartment inserts are OK and just fit a M body with modest or slim lens attached (such as M with 28 biogon).