check on eBay for some deals on wide boards that are better quality than your Lamar if you are looking to upgrade. As some people have said toe and heel drag is pretty easy to discover when you ride. Some boards that are goodfor big guys are, lib tech skunk ape, gnu carbon credit, gnu riders choice, K2 slayblade, Never Summer Heritage X, Nitro Magnum, there ard plenty of options to look into that would suit your needs, and i always do a ton of research before coming to a final decision.
Look at online sales eBay etc to find good deals, if buying second hand just be careful and inspect if possible. Geartrade dot com is a good place to look also. bindings IMO are pretty damn important when pairing with a stiff board, if you have a stiff board with butter bindings you wont get the most out of it and will regret what you bought. Look into Ride El Heffe, Ride SPI, Ride Double Agents, Rome Arsenals, Rome Targas, Nitro (Phantoms i think), Burton C60, Burton C02 ( both discontinued i believe). Anyways hope that helps a bit.
Boots im not very familiar with whats stiffest, i wear Vans Jamie Lynns (2010) and they are pretty stiff and comfy. Also i wear a 14/15 nike and my Vans is a 13 so it may be smaller for you.
Ohh any my setups are Gnu Riders Choice 166W with rome Targas and a Ride 168W Berzerker with El Heffe Bindings. (I am 6'11 270lbs size 14 shoe
my names's Petey and i have gigantic balls