When walking from Soi 4 to Soi 8, I saw new condos got available in Soi 6, where the road takes the turn. They can be checked out on weekdays between 10am and 5pm. Cheapest condo 26k/month. Both monthly and yearly contracts possible. You can check it out on:
Bangkok apartment in Sukhumvit, 100m from BTS Nana! Stylish and great access - PSJ Penthouse