Just curious JT....how does the lawn look?What happens if I take two American Pale Ale No Boil Complete 5 gallon beer kits and combine them to make 5 gallonsYou'll make really strong beer if it works. If it doesn't you'll make a high alcohol syrupy mess.
You have a strong chance of making something very bitter, or with too much "specialty malt" flavor (roast, caramel, etc). Doubling recipes works if you increase all the ingregients, including water. Doubling all the ingredients EXCEPT the water may overload the beer with hops or specialty malt.
Make sure the yeast you use has high alcohol tolerance. If you get through primary fermentation and you're bottling, there's a chance that the yeast may give you the middle finger and go on strike, leaving you with flat beer.
Consider just adding some simple sugar to your recipe to boost gravity: try a cup or two for starters.
Or don't. It's only beer. I did a "high gravity" beer for my second extract batch. Turned into lawn fertilizer. I learned some things. I tried tripling the amount of crystal malt in a beer for my second all grain batch. Turned into lawn fertilizer. I learned some things.
Years later, I'm still learning with each batch, but make much less fertilizer!