I remember the recent discussion here (on the GMB) about the Inca vase very well (I gave the name and a little bit of background history).
Yes, Inca is the name given to the vase by Carnival collectors. The maker is not yet known but is almost certainly Czech.
You can read about it here (yes it's my website too)http://www.geocities.com/carni_glass_uk_2000/Inca.html
And you can read about a fascinating recent discovery of one of the Inca's "sister" patterns herehttp://www.geocities.com/carni_glass_uk_2000/GiantLily.html
And here you can see the original query, David, where I identified the vase.http://www.glassmessages.com/index.php/topic,1081.0.html
Finally, to confirm "Inca" is not an original pattern name for this vase. And yes, Carnival Glass collectors do name patterns. It's essential. Virtually without exception, none of the Classic USA patterns were named by the manufacturers. It would be impossible to identify or have any form of data base reference without assigning names - and the assignation of pattern names for Carnival patterns has itself been a fascinating and much referenced study over the past 50 years.
Some of the European patterns were named by the makers - but only some. In our books (by "our" I mean Steve and I) we have always been very careful to include all names and "aka"s for every pattern we have written about. Some of the European patterns were given names by collectors long before it was even known they were from Europe. A lot of my research and writing has involved identifying European makers and discovering original names, if they existed. In my writings I include original names, if known. But not every European pattern was named.
We do not know an original name for the Inca vase.