There are quite a few examples of university groups and individuals making HI line observations - so, compared to pulsar observations, it would seem that HI line observation is an easier project to achieve success with for the citizen scientist radio astronomer.
While the HI emissions are much stronger than pulsar emissions, the complexity of the data analysis software required for HI line observations is not much less than needed for pulsar observations. Both areas of observation require use, and understanding, of techniques an order above, in terms of complexity, those required for simple total power (TP) observation techniques.
Links to Examples of HI Line Observations
There are a number of individuals or university groups who have published details of their HI line observations. In no particular order, here is a partial selection (# - indicates some extra-galactic observations are included)...
NOTE: This is a partial list - there are certainly more examples to be found.