Hey Ellejo, my hubby is about to self build mine for me, I know that Helen (Nellie) has a lovely dad that built some fantabulous one's for her but think she may be able to pount you in the right direction for where to buy ready made ones. She may even be able to order them for you?
There are some photies of everyone's set ups in another thread... I shall have a look and see where they are for you....
xoxox