I've written my own very rudimentary version of the sparkline graph that has twice the horizontal resolution at the cost of some vertical resolution by using the unicode characters █, ▙, ▟, ▌, ▐, ▄, ▖, and ▗. I was planning to try to add the various additional features (styling, width/height specification, data normalization, etc) that this package supports, but realized it would be quite an undertaking. I might make a pull request if free time allows, but otherwise I figured I'd leave the suggestion here if anyone wants to pick it up. Sample graphs end up looking something like:

▙▖▖▗▟  
█▙▙▐█▗ 
███▟█▐▄
█████▟█

That packs 14 data points into only 7 columns, allowing twice the data to be summarized in a single screen (NOTE: it looks better in a terminal with proper font support, github does an awful job rendering it).