I have been thinking the same thing.....outgrown the current house and need a another one for all the LEGO. A bonus would be more garage space as I want to garage more of my vehicles.
The only thing I would say is have a long term plan. Most houses don't make financial sense until 5 to 10 years in. Life can change.....Do you see yourself 1: Doing the LEGO reselling thing long term? and 2: what is your life going to be down the road in some years (job, happy with the area, family, budgeting etc?
For me I am only working in my current location for about 6 more years until retirement at the ripe old age of 39 . I don't intend to stay here so I purchased my current house as a rental property for some retirement income in the future. I can justify a second house to be eventually another rental house.
Think it through, take your time, calculate out a budget, plan for things to go wrong and reason out a smart plan.