I got my table from my Bernina dealer (although I'm not sure its actually a Bernina table) anyway, the adjustable legs with the suction cup on one end is available from them. You can order as many as you like (they sell them as replacements). so I'm sure most anyone that sells the tables would also sell the legs.
Someone on here used plexiglass and cut PVC pipe for the legs to make their own pretty inexpensively.