From considerations of recent polls and demographics, Trump appears poised to win all 5 of the April 26 primaries. Probably. However, I would expect some considerable doubt about that from some.
As if he does win all 5, it will be a significant story, a useful market might be:
"Trump to Win All 5 April 26 Primaries"
Such would follow the precedent of the Trump-sweep market which existed for the early primaries (until its resolution after he lost Iowa), but serve even more of a purpose in ways, as presently the individual state markets are getting rather close to 100%.