I put them on a par with PSV Eindhoven - not because of their recent successes (paid for or otherwise) but because their support is extremely localised to Hammersmith, rather than all over the country and/or overseas. In that regard, that would put Spurs on an equal term of "bigness" as Chelsea based on consistency of league positions. Newcastle are a difficult team to categorise in this regard, as they have the large local support, but their league performance is anything but consistent - in the space of three years they've been relegated, stormed the Championship, solidly mid table and battling for European football, and that's been their story for most of the Premeir League era.
You can argue the amount of Liverpool and Celtic fans in Dublin would make them a bigger club than I listed them as, but that says more about the quality and support the Irish league has than Liverpool or Celtic.