10 lbs is enough to make a 5 gallon batch. Your ABV just isn't going to be as high. I started a 10 lb batch a couple of weeks ago and my starting gravity was 1.082. If this ferments to 1.000, that would give an abv of 10.75%.
A 4-8 week turnaround is possible, but generally speaking, not very simple. A fast ferment that does not produce lots of off flavors is going to require lots of attention and a fair bit of work. Using 10 lbs of honey and a clean fermenting yeast with a high alcohol tolerance will help, but one of the best things to ensure a tasty mead is patience. Using even less than 10 lbs will decrease fermentation times even more, but leave even less honey flavor.
Also, nutrients are always a good idea for mead. As many people state, honey is very low in the nutrients yeast needs to be healthy. It can be done without them, but it's not recommended.
I would suggest using your 10 lbs, yeast nutrient according to manufacturer's instructions, and a white wine yeast like K1-V1116, Cote des Blancs, or Premier Blanc, and patience.
