The folder that I mentioned above (451 - 20" wheels) does have a 60t chainring and an 11t small cog which gives it a maximum of 109 GI which happens to be the same as my other road bike (622 - 700c wheels) with its 52t chainring and 13t small cog. But frankly the gearing is not what limits my speed on either bike except for a few downhill stretches or with a terrific tailwind.

It's easy to increase the highest gearing - the Schlumpf 'highspeed drive' BB will multiply the GIs by 2.5 and there are plenty of internal hub gears that can provide just about any range of gears you may want. The limiting factor is whether you have an appropriate engine to drive such high gears.