Medjool date palms are great for starters. You can get the seeds from store bought dates (unpitted), and they sprout and grow under any reasonable conditions (moist soil and enough heat). They tolerate periods indoors well and grow slowly. I have a few I grew from seed in my yard here in Florida.

I have tried the true date from seed, but seem to have better luck with the Canary Island Date (Phoenix canariensis) from seed. You also need to try Washingonia (either robusta, filifera or the hybrid filibusta which seems most common in the East). They are fast from seed and don't even require bottom heat (but being in Minnesota, you should use bottom heat). Seed just needs to be fresh (you can try eBay). Also, Butia (Pindo palm) is a cold hardier palm but may be slower than Washingtonia. Actually, I reread your post and see you want a slow grower. I would still consider Butia (but it like Washingtonia wanna be BIG palms. Windmill palms are another choice. Have not grown these guys from seed (but from seedling starters), have maybe a dozen of these guys in the ground and in containers. They are cold hardy enough to sail through a NJ/Zone 7b Winter even with prolonged snow and ice.

The only other consideration with these palms mentioned above is their potential to inflict injury to fingers and EYES. I just LOVE Date Palms, but in the house I would stick to Pygmy Date (and they too are somewhat barbed). The leaf petioles on Washys are also very sharp; Butia/Pindo palm and windmills are not prickly in the least. I overwinter my Canary Palms, Washingtonias, and very large, prickly cycads in the big, sunny, loft garage so and would dread having to move those into my house (dangerous, especially with kids..., animals seem to avoid the risk of injury quite well though). Good luck!