Stumbled upon this post and also read your personal introduction on Mike's Prospero site and was wondering what you like about Francescatti's interpretation. I often find his tone uneven (Menuhin has the same problem as far as I'm concerned), and he throws in a lot of vibrato now and then. On the other hand Casadesus is wonderful, a great pianist. The Grumiaux/Haskil set is a golden standard for me, despite the not very good, hard sound.
A great "older-style" interpretation of Beethoven's cello sonatas is the Fournier/Kempff set - in my opinion, of course
I still find it very hard to talk sense as far as violinists go ... I've got no issues with tone or intonation of Menuhin or Francescatti. In fact I'd wish more of Francescatti's recordings were available! I've got both Music & Arts set (the 3CD compiling some Columbia studio recordings, mostly sonatas, and the 4CD set of live recordings of concertos), and I got the Masterworks 2CD set with some more concertos and I just love his overall feel, his touch, his way of approaching things in what to me seems to be a clean cut manner - "aufgeräumt", never pretentious, yet still rather "French" in feeling and tone.
Fournier/Kempff was not on my radar, but Fournier/Gulda has been in my shopping cart for months. Guess I'll go for both, eventually ... but then I might try and find some HIP version of those sonatas, too, who knows