Simple Furniture raisers measuring six inches / 15 cm fit nicely inside each other so take up less room in your suitcase for those Inclined Bed Therapy Holidays. Fortunately they come in packs of 4 for around £10 on Ebay and elsewhere. You can buy stronger ones and even wooden raisers or make your own custom designs by filling plastic bottles with cement and sand mixed with a little water. In this you can insert castors at the bottom and upside down at the top so the bayonet is protrusinf with the wheel embedded in the mortar. You will need to let it set for around a week before using it. The tough plastic bottle provides a durable external coverto save scratching your floors. I like this method. You can also embed a large threaded bolt into the mortar so it can be screwed onto your bed legs when set. You will need to drill a hole slightly smaller that the threaded bolt in the bottom of the bed legs to avoid splitting the wood. The one's shown are 5" raisers but with timber placed on the bottom of them with a square cut to the insde measurement screwed and glued on you can make them up to any height you like.
You can fit one inside the other to raise the bed higher because you have 4 in a set.