According to a number of websites the RX-V1900 won't be available until November, however reading another site, it appears a few people have got their hands on some in the UK already.
The best prices I've seen the RX-V1900 advertised are...
http://www.hifix.co.uk/sku.lasso?item=e2bccf83d057b9a57c1752220010aefa
http://www.petertyson.co.uk/ebuttonz/ebz_product_pages/yamaha_rxv1900.shtml
Yes, I think you are correct, the RX-V1900 only scales analog inputs, whereas the RX-V3900 scales (and more) both analog and HDMI inputs. I personally prefer the look of the RX-V3900 as it has more video capabilites (including a handy 2nd HDMI out) as well as being a "network" reciever.
I have asked (via this forum) whether WHFSV plan to review either the RX-V1900 or RX-V3900 (I believe sonically they'll be pretty much the same) in the near future, but so far haven't heard anything back (appear to be ignored ;-)
I'm keeping a look out on the other forums and the HCC website for early reviews. If I find anything I'll let you know.