Just watched this video (Men's Craft, A smart idea from a metal profile) His welding table is made of rectangular hollow section (RHS) and has an inbuilt flush turntable. I've always liked the foot-operated turntable the TXSVIKING fellow uses, but this one might be even better. Seems a good idea to me, especially if it has positive indexing and is lockable. Makes jigging up pieces with odd angles easy as table slots through which clamps pass could be set to any angle relative to the fixed pieces. Of note also is the thing he builds - a stand for a nibbler. Which could be adapted to a die grinder (see michaelcthulhu, He-Man power sword build part 1 at about 5:33).