"I can see why it appears a viable financial proposition to look at a Taig lathe and the addition of 2 or 3 extra lathe beds when compared to the price of a dedicated cue lathe. There is a relatively simple method of aligning and fixing several lathe beds accurately, and it is only possible because as you state "the steel ground surface and dove tail are finished to a standard". All that is required is the lathe beds, sets of mounting bolts, a piece of 2x4 ( over kill?) box steel about 48" long for the bed, pre drilled with over size mounting holes, a good quality 48" straight edge, a supply of a 2 part epoxy (rapid?), a strong friend ( for when the project is completed) and access to a true flat surface -a large surface table, or a long lathe bed, maybe the neighbour's marble kitchen worktop!
The method - invert the lathe beds and set them up end to end, align them with straight edge, mix epoxy and apply coating to the mounting plates, lower the box section with greased dangling mounting bolts into position and let time and gravity do the work, clean excess epoxy before it sets on surface table or kitchen worktop. When the epoxy has cured nip up the mounting bolts. Some locating dowels in each mounting plate would not go amiss. With your strong friend turn the assy. over and install in req'd location. The beds are aligned as accurately now as they were inverted."
"My 'bookends lathe' constructed to work on cylinders and barrels, picture is posed, the gap arrangement is forward planning just in case I have some large diam., work to swing, no riser blocks are needed for the head and tail stock."
"My bookend lathe has the sewing machine motor drive revised, it could really do with halving the speed again but it can handle crowning and breech work on barrels and cleaning up the ends of compression cylinders. Pics of that show another use for my never ending supply of 2 1/2" ally channel and left over pulleys from my Thread Box project."