Well the old saying goes, you cannot have enough clamps. Last year
after my work/assembly platform collapsed under the weight of 20+ clamps
and the cabinet, I can say I have enough clamps.
Anyway there appears to be a knock off of or "Made by Bessey", Bessy
clamp being offered by Lee Valley
Compared to the Bessy Revo clamps they differ in color and the handles
will bend to increase the ease of applying clamping pressure. Other
than that including the copy of the less than desirable design of the
foot on the end of the bars the seem to be a good deal.
Introductory price on a set of 4, 2-23.75 and 2-39.5" clamps is $139.00.
Other sizes available.
http://www.leevalley.com/US/wood/page.aspx?cat=1,43838,43844&p=72719