We are having the same issue with this exact same model – WT8360SE.
Like the previous reader, we have also tried using xfer to load the image from wyse – http://www.wyse.com/serviceandsupport/support/dlOraFW.asp?which=47&model=8360SE
When loading the smallest of these images (63,547KB), we get 93% of the way done and then it fails – out of space.
Our next step was to obtain a working model and then use nte extractor to get a good 8360SE image we could use to deploy to the lot we purchased.
If you have an alternative image for these devices that will work with xfer or nexfer we would also love to try it.
Any help would be greatly appreciated.