Hi fm2002.
I asked Pops motorbike hire about bike hire for you, and the guy I spoke to said they will hire bikes that you can take to Laos for 1000baht per day.
He said they organize all the paper work.
He gave me he's bosses number (086-9111218) and told me you should booked though him.
Im not recommending Pops. Im only telling you what they told me.
If you want to deal with this company, its up to you.