Last two req 9 str -2/+45 stance echos have sold for 300-350e (to me and Bestest, respectively). Based on that, I could take a wild guess about the value of your shield, but I think the solid info is more useful.
These 1 offs are a huge gamble... It could go 150e+ or it could garner 0 interest and barely get 50e... Highend, see what happens when people start bidding. My guess.. 100e+ should be pretty easy. :S
I recently bought a q9 Str -2^st +28 (always) Echovald for less than 50e. It's possible that I'm wrong, but I wouldn't think that +44/stance would be worth twice as much.
Not everyone's noticed that stuff just isn't selling lately. I've got a bid in on an Amber Aegis with identical stats to your Echovald that's drawn almost zero interest (c/o of 12e). Obviously Ambers aren't as popular, but that's not the whole story. For whatever reason, people just aren't buying.
Think I saw an Eternal with those mods get 200-250e offers not too long ago, but my memory can be playing tricks on me... So probably 250-300e with some luck