Or you can do like a guy I know who trains Jiki shinkage ryu, he went out and got himself a log and did some rudimentary whittling of one end so he can get his hands around it, and he just swings that around.
Funny you should say that - I have a tree branch from the back garden that I did just that to. :-D Unfortunately after it dried completely it's also only just under one kg.
That looks like a very nice bokken! But it looks suspiciously like the one I have for partner practice. If you happen to have a chance to weigh yours I'd be interested to hear what it weighs.
Ok so a quick google found this:
Just the weight I want. Might be the best option.
I know someone who at least used to make aikido weapons - I think I'll ask them as well before deciding. Thanks for the tips so far, keep them coming!