There are a couple of horizontal units that can be set up to do what you want. I think ''Lighthouse'' in California makes one. They tend to be a pit pricey, and while the Lighthouse unit is beautiful and all stainless, etc. , I''m not able to swear to it''s reliability.
I use an Ideal vertical
windlass that has my primary
anchor fed through and into the proper hawspipe to stow low center in the aft bow section, as it is all chain. The secondary bow
anchor is also chain, but smaller. To haul it, I must stopper off the primary chain and seperate it from the gypsy, then wrap the secondary on the wildcat and hand tension it in. The secondary ends up on the deck, but once the
anchor is chocked, I clean everything up and stow it while the boat settles back on the primary
anchor.
From there, I can return to the cockpit and start the engine and haul the primary from the helm. It all feeds nicely into it''s pipe and the
anchor self
chocks securely. Once well out of the achorage and under way, I can
cleat down whatever I need.
I can not think of any
windlass that will allow you to simultaneously or alternately handle two
anchors without being forward and manually clutching each side. I suppose you already know that and are thinking more about that beautiful dual chain piece of equipment out there.
Good luck with that, but be willing to pay heavily for it.