I recommend the 8x4 size over the 4x4 size. If you had an 8x4 coop, you'd put your access doors on the 8 foot side so you'd only have to reach across the 4 foot span when cleaning out.
I don't have an elevated coop, but have always thought that if I did I would elevate it enough so as to be able to put a wheelbarrow up to the access door and just reach in with a rake and pull the dirty bedding out into the wheelbarrow. This would have the obvious benefit of making cleanouts of the coop monumentally easier but would also provide enough height under the coop to reach in with a rake for cleaning or even crawling in to retrieve an injured bird (or a stubborn broody hen that decided that under the coop would be the perfect nesting site).
I don't have an elevated coop, but have always thought that if I did I would elevate it enough so as to be able to put a wheelbarrow up to the access door and just reach in with a rake and pull the dirty bedding out into the wheelbarrow. This would have the obvious benefit of making cleanouts of the coop monumentally easier but would also provide enough height under the coop to reach in with a rake for cleaning or even crawling in to retrieve an injured bird (or a stubborn broody hen that decided that under the coop would be the perfect nesting site).