Excellent job! Before I bought my HQ, I did sort of the same thing. Bought a sofa table at a garage sale for $10, then had hubby put 1/2 sheet of plywood of top. We then cut a hole and buried my machine, similar to yours, only all the way around. I covered the table with floor tiles, and had a lot of room for quilting! It also served as my cutting table, as I could put my bigger cutting on it as well. I used it for 3-4 years, then finally went a little larger :)
Good creative thinking! Enjoy :)