This is a tree that slowly matures to 15-20 feet.
It would be better to cut it off at the ground than to just top the thing. You could however drop prune and reduction prune it but it would take a bit of skill to maintain it's form.
Think you can move it? If so beging root pruning to make a root mat of fibrous roots closer tot he stem.

yes, you can top it. but i don't know what it currently looks like. once you cut the leader you can promote a branch to a leader.

Can you top? Sure. Should you top? No way. Topping a tree not only makes for an uglier form, it also open up the tree for disease and rot. Read Alex Shigo (I suggest Tree Pruning: A Worldwide Photo Guide. Has great pictures and is written for someone with little knowledge of tree biology) for tips on how to properly prune a tree and maintain its form. Use the bloodgood as a learning experience for your self. Read-up on proper techniques and practice.
The coolest tree I ever saw was a Mango (normally 50-60ft mature)in Hawaii that had been pruned from the beginning of its life to be only 7 feet tall and weeping (so as to make it easier to pick).
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I agree with bamboo. It has probaly come close to it's full height. Now it's going to get a little wider and the trunk is going to get fatter and start looking real good. I have two of them against my house. A little to close but you can shape them to fit the house. I did some severe spring pruning last year and regretted it.

I have drop pruned the taller of the two over the years and it is real nice like an umbrella. You can open it up and make airy and keep the canopy high. My other one is short and squat and will need to be moved next spring.

Like Trilliophile indicated, in order to keep it small you need to start when the tree is you. I tried to make it small too late and regretted it. It will have to be moved to a better site.

good luck.

I "top" mine and keep it at 15 feet. I cut carefully leading vertical shoots only THRU-OUT tree. This will promote growth of horizonals and make tree look great. You have to do it about 4X per year to cut leaders when still small enough not to leave huge stumps that looks "topped". Places where you cut off vertical leaders when small will blend right back into bark. Do it carefully and err on side of cutting less - you can always cut more after leaves are off in fall and you can see branch structure better.

'Bloodgood' grows over 30 feet high in some climates. If you have a single storey house, your tree may be just getting started at one storey high.

J. Vertrees advocated pruning to control size in his book JAPANESE MAPLES, saying it was the only way to maintain a large number of trees on a small lot. However, he wouldn't have meant topping in the usual sense, as you appear to be using it here, where a normally shaped tree is suddenly and harshly decapitated because it has exceeded a certain height. If you wish to end up with a nice specimen, don't do anything that involves cutting into old, hard wood or stems of a significant diameter, say more than 1 inch thick (at least until you are more experienced and familiar with pruning).