since most guinea pigs are a kilo, I can't imagine a rabbit that small except for a netherland dwarf breed - and they're still a bit bigger than that. There are mini lops, but they're not particularly small, they're just called mini lops for some reason!
rabbits are notoriously hard to sex correctly, which is why when you buy a pair of babies, you can end up with them mating after a few months, when one turns out to be the opposite sex to the other! So I would advise just getting one rabbit for now - boys make better pets but females can be spayed, if you can find a competant vet - it's a delicate operation and rabbits must NOT be starved before surgery, unlike cats and dogs - and also they should have a different type of anaesthetic, and often chew out stitches or have a bad reaction to them.
Really I think see if a breeder who cares for their rabbits well, has an adult rabbit she doesn't want any more. This way you will be able to see if the rabbit is easy to handle, tame, healthy - whereas a baby rabbit will be easy to handle for about 3 months, and then when it starts to reach sexual maturity, behaviour and aggression problems usually start too.