If you thought soy made it watery, rice milk would be worse! It does taste like rice.
I don't use creamer, but I do love chocolate in cold coffee- 1/2 and 1/2.
I've know people who use Silk creamers. There's reg., french vanilla, and hazelnut. They do have more "body" than the milks.
I believe there's a coconut creamer - maybe So delicious?
Have you tried vanilla soy milk? Or different brands? I wouldn't like unsweetened soymilk, even though I don't use sweetener in my coffee, but I think I would like vanilla, or even the original (sweetened) ones. They seem to be creamier. The same would apply to almond milks. Unsweetened always seems more watery to me.
Don't let the perfect be the enemy of the good