5nines is in that building, they list available carriers on their spec sheet, it is a pretty respectable selection. Unsure of how the MMR or cross connects work in building though.
https://datacenter.5nines.com/wp-content/uploads/sites/62/2019/10/5NINES-Data-Center-PDF.pdf
From: NANOG [mailto:nanog-bounces@nanog.org]
On Behalf Of Mike Hammett
Sent: Wednesday, January 22, 2020 9:02 AM
To: Daniel Corbe <daniel@corbe.net>
Cc: Nanog@nanog.org
Subject: EXT_Re: Carriers
Maybe those with their own glass, but they wouldn't know anything about anyone coming in on IRUs.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
Midwest-IX
http://www.midwest-ix.com
From: "Daniel Corbe" <daniel@corbe.net>
To: "Rod Beck" <rod.beck@unitedcablecompany.com>
Cc: Nanog@nanog.org
Sent: Tuesday, January 21, 2020 2:30:00 PM
Subject: Re: Carriers
On Tue, Jan 21, 2020 at 12:47 PM Rod Beck <rod.beck@unitedcablecompany.com> wrote:
Does anyone know who are the providers in this building? US Signal is there. Anyone else?
222 West Washington Ave, Madison.
Surely the landlord would have a list of carriers providing service into the property.