Five ideas so far:
Cambrian 1F (proposed) – Chepstow – Raglan – Brynithel – Usk – Chepstow (100km) – 1640m ascent
Cambrian 1G (proposed) – Abergavenny – Hay-on-Wye – Tredegar – Blaenavon – Abergavenny (100km) – 1700m ascent
Cambrian 1H (proposed) – Hay-on-Wye – Hundred House – Knighton – Penybont – Hay-on-Wye (105km) 2250m ascent
Cambrian 1J (proposed) – Newtown – Llanfair Caereinion – Llanbrynmair – Machynlleth – Staylittle – Newtown (110km) 1630m ascent
Cambrian 1K (proposed) - Maesteg – Treorchy – Hirwaun – Maerdy – Mountain Ash – Ferndale – Maesteg (106km) 2200m ascent
1H relies a bit on pubs being open, which will probably mean that no one ever gets to finish it. On the grounds that if you are able to get proof of passage you won't complete the ride and if the pubs are closed you can't get proof that you did complete the ride.