There are plenty of popular padding schemes in use today. ANSI X.923 and PKCS#7 come to mind. However, all of them work on single bytes at a time. This is hardly surprising: padding for cryptographic purposes is usually just to 16 bytes and a single byte can hold the value 255.
I was wondering if there was any generally accepted method of padding when we need to add more than 255 bytes of padding. PKCS#7 obviously wouldn't work since you'd have to have multiple bytes for every byte normally. ANSI X.923 could be modified slightly to use more than one byte at the end to store the length of the padding, but this too comes with its own problems, namely that it doesn't work for every combination of inputs unless you do some dirty workarounds to manually take care of edge-cases, and even then I'm doubtful it'd work.
The solution I came up with was to simply run PKCS#7 multiple times. What I mean by that is if we want to pad 300 bytes, then pad up to 255 normally (by adding 255 bytes of value 255), then pad again up to 300 (by adding 45 bytes of value 45). When un-padding, you'd simply remove the top layer of 45 bytes, check to see if the next 255 values were all 255, and if they are, remove them all, and repeat.
I can't find a mention of anything similar to this, however, hence the question. Is there a standardized, accepted way?