That doesn't sound very mobile with the cement part! haha
I have a couple pole bean trellises that I made out of galvanized electrical conduit. They are just in the shape of a 3-sided only rectangle. Instead of pushing the pipes into the ground, I hammer 2 green metal stakes (3-4') into the ground and the pole tubes fit nicely in the crook of the stakes. I then use twine to connect the trellis to the stakes.
You're probably thinking this doesn't sound very mobile, but it actually is very easy to move. You just pull up the stakes and put them in the ground somewhere else.
The other mobile trellis I'm trying out this year is an old swingset! Can't wait to grow my cucs up it.
Good luck to you.

Here's a link to a post here with a pic of a free-standing trellis.

Here is a link that might be useful: freestanding trellis post