There are usually about 5 or 6 sets in the 32" range.
The reson 17 show on the website is both new models (yet to be released) and older models (usually 2gens old) are kept there so interest can be generated and specs are available for older stock still on the shop floors.
The smaller sony sets are replaced about every 6 months, often slightly faster than this, which generates the extra models you can see on the site.
For 32" and 1080p you looking primarily at the V and W series sets (current models 32V5500 and 32W5500, older gens are the V4000/W4000 series) With the W being slightly better spec than the V, but its marginal.
There is also the E series, lower grade set but with a 'unique picture frame' case so there is a premium on the set and its not great value.
Most of the newer Sony sets are KDL-XXYZZZZ
With 'XX' being screen size.
'Y' being the Series - The 'higer' the letter the better i.e Z is considered the best
and 'ZZZZ' being the spec I think so again, higher numbers = newer (and I'd hope, better)
Close but not quite, the series lettering is not logical, as although in general the later the letter - the better the set, this is not always the case.
U < P < S < D < E < V < W < (E)X < Z
Although not all ranges are available in each screen size, and the specs are shuffled down the lettering at every refresh.
Think thats confusing as a consumer? You should try working for sony, keeping up with constant refreshes and subtle case/spec changes, then conveying that to customers...