Not 100% sure what you are trying to say here.
You want second hand db set but you also want a custom db set perfect for your perceived needs?? Unfortunately if you buy second hand you are limited to what people in your area are selling.
Don't understand what 1-6kg no skipping means?? You can buy a skipping rope pretty cheap from most sporting stores, even K Mart etc sell them.
You said you are buying it for your wife, yet you want to start at 7kg?? Most women won't be lifting 7kg for a lot of db exercises, I know a lot of men who won't lift 7kg for certain exercises. a 35kg Db is huge and I doubt your wife would ever be doing any exercise that requires a 35kg db.
May be contact Gymdirect or similar sellers to see what they have.