Someone is going to disagree with me, but I'm going to say it anyway, wetsuits are obsolete. Buy a good drytop if you don't have one already and use what you already own to layer underneath it.
I'm also going to give away my $1MM idea to some entrepreneur. I use my primaloft jacket on those extra cold days under my drytop and since it insulates even when wet and it's like wearing a down jacket. I'm wondering why no one makes a paddling specific version yet without a zipper and all the bulk. I have bottoms that are the same material and I've even worn those under my splash pants and that works great, too. Maybe it's cost-prohibitive to produce, but it works like a synthetic sleeping bag. Lighter, even when wet than fleece, too. There's a lot of winter clearance sales going on right now, maybe you could pick one up cheap. You'll use it for everything once you own it.
Too stupid to come out of the cold