I got this in the mail today:
http://www.vaselineglass.org/webbtazza.jpgThis piece is shown in Cyril Manley's book, DECORATIVE VICTORIAN GLASS, color photo #209. Other than Manley's version is etched and mine is smooth, it is the same piece. The same etched Tazza is shown in Hajdamach's book, BRITISH GLASS 1800-1914, pg. 316. Hajdamach does not give an attribution, other than Stourbridge region, late 19th century.
In Manley's book, he makes reference in the write-up for #209 to photos #193 & 199. The #193 is due to the etching, the #199 due to the twisted stem. #193 is by Richardson (according to Manley) and #199 is Webb (according to Manley).
In Hajdamach's book, he has a big write up on Richardson pioneering the etching process, but I could not find anything in the 'etched glass' chapter that referenced Webb.
I also know that there are several pieces shown in Manley's book that have since been disproved. I would sure like to hear what the general concensus is for a maker. I am leaning towards "most likely Richardson" due to the etching, and the leaf-shaped feet.
Regards, Dave
aka: Mr. Vaseline Glass