suggestions for largish gantry for laser (and possibly router)

Sigh. First I had a sherline cnc with, IIRC, about 4" x 10" travel.

My wife was always coming up with things she wanted made that needed
just a few more inches travel.

Then I got my shizuoka with 29" x 15.5" x 16" travel. Last night we
were cutting tombstones out of 1" foam with my 17 watt CO2 laser and
kept running up against the travel limits again! lol. I ended up
taking off the rear way cover to get an extra 2" of y travel...sheez.

So now my wife is pushing me to build a 4' x 8' cnc router/laser
engraver so we can just toss in full sheets of plywood, mdf, foam,
etc. Since it is not all the time that your spouse wants you to
spend lots of money on machinery, I figure strike while the iron is
hot. :-)

I am thinking about building something out of welded square tubular
steel stock. Someone either on here or the emc group built a chain
drive router with angle iron ways that was actually relatively
accurate when milling even aluminum. That sounds like a potential
route for me to take. Pitty my welding skills are so poor...

The forces for the laser are negligable. I have a 50 watt laser I am
thinking of mounting to the gantry frame parallel to the 8 foot axis
that fires into mirrors moving on the y axis. Pretty standard way of
doing this..shouldn't be hard.

I also want a machine that can route through a full sheet of 3/4"
plywood. The laser is not strong enough to do that, so I need to
build this machine rigid enough to support a wood router.

How many people have had success with the angle iron/chain drive
setup?

thanks,

Rick