Yes it does exist in Scotland at same rates as the rest of the UK. We applied ourselves for OH and were refused even the lower rate. Reapplied with a benefits advisor from the local CAB completing the forms and were awarded the higher rate.
There IS a difference in Scotland though, which is that if you go into respite care or permanently into a residential Care Home and are self funding, then Attendance Allowance stops after 4 weeks, whilst you continue to receive it if self funding in the rest of the UK. This is because the DWP has ruled that as Care Home residents in Scotland have £177 per week of their fees paid by the Scottish Government under 'Free Personal Care for the Elderly' legislation, they are already in receipt of public funds for this purpose.