It's typically a little bit different in adult.
Yes there are a few old school pay per email / pay per free signup sponsors out there that let you host the form.
But in general in adult when you say Landing Page - do you mean tour? (preview & sales page for a paysite typically) or do you mean that you want someone to build you a better form/preview to promote an existing product/site?
I do a fairly large amount of MVT (Multi Variate Testing) for adult sites, and I can tell you that what typically works for mainstream pages is frequently not the same for adult.
That's probably not too surprising as generally you are trying to inspire lust for adult, and with mainstream you are generally trying to inspire something else. (Greed, fear of loss, acceptance etc).
I would suspect that dating would be where there would be the most overlap in best practices.
Pricing & positioning is also generally different. Typical adult tour (4-6 pages) is generally $600-$2500 wholesale depending on vendor. Typical LP on WF from my completely nonscientific and incredibly lazy research $35-50.
Multiplying x5 so it's apples to something or other and it seems mainstream LP designs are less expensive. That's also not so surprising, I have a fair number of vendors who only work on mainstream projects for me who will not do adult. I don't have any adult artists that turn up their nose at mainstream.
I generally lurk, and this post is long and rambly so my apologies if it wandered.
Probably easier for me to say - PM me your contact info and if you want I will spend a few mins with you discussing what you are trying to do and get you some good adult referrals if you like.
