I'll try to answer as many as I can here. It may take several posts. But, this belongs better in some other forum in the case of some replies.
To NJTRailfan, ALL of the VIA (ex-CN) 10-6s were former US railroad cars. They had just about every type of Pullman Standard 10-6 ever built, including Gilbert's famed ex-MILW 10-6s. There were also a few ACF builds on CN's roster ... I don't recall whose right now. CP had NO 10-6s! VIA purchased a few ex-Amtrak 10-6s (SP Sunset Ltd. as I call), but I don't think that any of CN's 10-6s made it to VIA.
To CarterB, Amtrak refurbished (and HEP equipped) a few 11 bedroom sleepers for AutoTrain service. Mostly, these were ex-UP STAR and PLACID series cars (these had different floor plans, since the STAR series were originally 5 DBR lounges). Also, there was at least 1 SILVER-series 6 DBR/5 Compartment car in this group ... I believe from the 1956 DZ (although it may have been a 1952 CZ car).
And, for jhdeasy, I can recall 2 different series of center bedroom 10-6s. First, there were a lot of these from P/S from the 1950-series C&O order. Nickel Plate tacked a few additional cars onto C&Os existing order (well before C&O started to dump its excess cars). Once C&O realized that it had over-ordered, these cars went in all directions ... ACL, B&O, D&RGW, IC all purchased come of the C&O order. Curiously, D&RGW converted 5 of the roomettes into open sections, because these sold better on their routes. The ACL cars survived into Amtrak; the Nickel Plate cars went to CN. There was also a series of Budd-built 10-6s: 9 cars for the 1956 Denver Zephyr, and a handful of similar cars for the Missouri Pacific (in 1956 also). The curious feature of the MoPac cars was that these rode on 6-wheel trucks! All of the CB&Q cars made it to Amtrak; NONE of the MoPac cars did. I can't recall any ACF-built center bedroom 10-6s. P/S had some other variations ... 10 roomettes/5 double bedrooms for CN/GT&W and Erie, and 8 roomette/6 double bedrooms for Rock Island. Amtrak eventually did purchase the 8-6s, and, for a while, leased (?) some of the CN 10-5s (these frequented the Montraler/Washingtonian in the early days). Many other center bedrooms configurations existed in various forms (see MILW, NP, GN, SAL, ACL, AT&SF, UP, and many others), which contained various combinations of sections, roomettes, duplex roomettes, double bedrooms and compartments. The best source for this information is the old Wayner book, CAR NAMES, NUMBERS AND CONSISTS, if you can find one!