My cutting table and ironing board are both fairly tall (I'm 5'6") and keep me from having to lean over (sure hate to cute at a dining room table which I did last week when cutting out flannel jammie pants for Christmas). But my sewing table is right at 31" and I still think it's too tall--my machine does not sit in it but on top--so that means the machine bed is at about 34" and my elbows are not at that 90 degrees--and my shoulders and neck know it! I plan to literally take a saw to it and cut it down over the winter! Do any of you ever set the machine on a higher surface and stand up to sew? I sometimes do on my cutting table--makes for a nice change for my body.

Another thing to think about.... an office chair that can go up or down is a must for me. I am 5'2" and I sew at the height of a regular dining table, which is the same height as the normal sewing machine cabinet. This, also, allows me to put a folding table up close to my sewing table and let it help support the weight of a quilt when I am sewing the longer rows or putting the binding on. Or, I can use the extra space as ironing area or trimming area. When you start changing the height of the typical table, it can throw other things off.

Now after having said all that, if you can do a cutout for your sewing machine and bring it down to level with the table, then that is the best solution. This is one way https://www.youtube.com/watch?v=mbE48Saa-Pc
Another idea http://www.instructables.com/id/Make...able/?ALLSTEPS

There are more out there. I searched for "flat bed table for a sewing machine"

I am also 5'4" and my sewing table height is 27" which is the best I can do and comfortable. (Any lower and my legs won't fit under the machine--Lol.) My machine is set flush with the cabinet top. The cabinet top was 29 3/4" high when I bought it. I removed the casters and put on sliders to lower it so that my shoulders and back wouldn't hurt. You may need yours a bit higher if your upper arms are waist length.

Hope that helps!