Brett I'm glad to hear from someone that has an X-3 and is happy with it. Also, your wanting it down around 30" tells me my 36" bench would be way too high. I'm a tad under 6 ft. tall...what about you? Just comparing. I'd hate to get it too low and get the 'ol back out of whack again.
The cust. svc. fellow that recommended the 1st stand linked to above said the mill would have to be bolted down to the top with 1 3/4" lag bolts. It's 30 1/2" tall which would put it in the height range we're looking for and the price is OK. I just worry about it's rigidity. It's rated for 700 lbs so it may be OK.
I don't have any nice 4x4's squirreled away and heck, they're pretty darned expensive to buy these days.
My other option is a surplus phone equipment rack I have lying around that's built very strong. The main structure is 2" alum. angle (webs are 1/4" thick) with sheet steel sides. It's about 6 ft. tall but I was thinking about sectioning it down to the appropriate height and bracing the top. The only problem is that's another project to complete before I can get to milling parts. I wanna play with my new toys NOW!
"Accuracy is the sum total of your compensating mistakes."
"The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton