"so you found a nice board from the as-is room with all 4 edges finished (ie. a cabinet door) for a price you can't pass up and want to turn it into a coffee or side table, but don't want to spend a lot of money or have to do a lot of engineering. well, here's an easy solution for a base ... as long as medium brown suits you.
acquire a ramberg bedside table. measuring roughly 18" x 14" x 16", it's big enough around to serve as a table base. more importantly, however, is that this piece is constructed with 7/8" thick sides and shelf, making it very sturdy. with all 4 sides finished and a low $19.99 price tag new, it's affordable too.
just build it up like it's supposed to be - 6 dowels + 6 screws, but omit the glass and pegs. then use 4 small L-clips + short screws on the inside top edge of the ramberg and secure the new top. done.
this is pictured with a wood veneered door (15.5" x 30.5") that was purchased for a measly $0.49."
