Eudos ab Euddolen - It seems crazy but this appears to be my 55th great grandfather...

I don't think it's unusual in a case like this with so much Welsh and royal descent, all of which is fairly well documented.

Eudos ab Euddolen is my 59th great grandfather.

This is, according to GeniCom, a line that runs to him via Brabant, Hohenstaufen, Burgundy and Normandy....
My proven paternal and maternal 17th great grandfather: John I the Victorious, Duke of Brabant and Limburg
→ Henry III, Duke of Brabant (his father) 
→ Maria von Hohenstaufen (his mother) 
→ Philip of Swabia, King of Germany (her father) 
→ Beatrice of Burgundy (his mother) 
→ Reginald III, Count of Burgundy (her father) 
→ Etienne I "Tête Hardie" comte de Mâcon et Bourgogne (his father) 
→ Willem "the Great", Count Palatine of Burgundy, count palatine de Bourgogne (his father)
 → Adeliza (Alice) or Normandy, Countess Of Burgundy (his mother) 
→ Judith of Brittany (her mother) 
→ Conan I 'le Tort' de Rennes, duc de Bretagne (her father) 
→ Judicaël Berenger de Rennes, comte de Rennes (his father) 
→ daughter of Berenguer (his mother) 
→ daughter of Gurwent (her mother) 
→ N.N. de Bretagne (her mother) 
→ Erispoë II, king of Brittany (her father) 
→ Nominoë, king of Brittany (his father) 
→ Erispoë "the Elder" de Broërec (his father) 
→ Budic de Poher, Roi du Bretagne (his father) 
→ Daniel Dremrud, King of Brittany (his father) 
→ Gerwenn de Cornouailles (his mother) 
→ Concar Cheronnog ap Gradlon, Prince of Cornouaille (Brittany) (her father) 
→ Count Gradlon ap Judicael (his father) 
→ St. Judicael ap Hoel (his father) 
→ Hoël III ap Alain I, Emyr Llydaw (his father) 
→ Alain ap Hoel Fychan (his father) 
→ Rimo Tymyr ferch Rhun, of Gwynedd (his mother) 

→ Perwyr verch Rhun (her mother) 
→ Rhun Ryfeddfawr ab Einion, Prince Of Lesser Ebrauc (her father) 
→ Einion ap Mor, King Of Lesser Ebrauc (his father) 
→ Mor Maeswig ap Ceneu, of Ebrauc, King N. Britain (his father) 
→ Ceneu ap Coel Hen, Saint, Brenin Rheged & Catraeth (his father) 
→ Coel Hen ap Tegfan, King of Northern Britain (his father) 
→ Tegfan Tasciovanus ap Deheuwaint (his father) 
→ Deheuvraint ap Tudbwyll (his father) 
→ Telpwyl ap Urban (his father) 
→ Urban ap Gradd (his father) 
→ Gradd ap Rhyfedel (his father) 
→ Rhyfedel ap Rhydeyrn (his father) 
→ Rhydeyrn ap Endigant (his father) 
→ Eudigant ap Endeyrn (his father) 
→ Endeyrn ab Eneid (his father)
→ Eneid ap Eudos, Brenin Powys (his father) 
→ Eudos ab Euddolen (his father)

Eudos ab Euddolen is my 60th paternal and maternal great grandfather.

If you have a direct unbroken paternal line of descent, then yes, I would say that is exceptional.

When you look at research done to prove historical remains, as an example King Richard, a lot of effort went into finding 2 descendants who had direct lines of descent from his relatives, and that was much closer in time.

The ancient Welsh lines here are well researched. I think you can feel reasonable confident in the ancient connections based on what sources are available for everyone to make connections. The work would be in making sure all of your connections leading up to those times are accurate.

Dear Kerri Amelia, Yes it appears to be an unbroken line of paternal decent. I had accidentally gotten there by manually clicking on the "son of" link in the profile that is my 5th great grandfather Thomas Joseph Powell 50-60 times until it ran out in the year -63 BCE. Nothing but father and son all the way back. I am just not sure if this is very rare or not... I am a documentary film maker and wondered if it might make for a neat short film.

Stephen Powell Others have written best selling books based on what they believe to be so about their ancestry, so hey, why not?

I think a documentary about the research process would be interesting, even if you have a different final outcome than what is suggested here. For example, have you been to Wales? What do you know about the "gateway" (first ancestor) from Wales to your current country? (I am assuming you live elsewhere, and that is why this is of interest.

I have cousins in Wales who have very deep roots to the same area spanning a very long time, so for them it is a bit more usual to find connections that run back quite some time. I do not know anyone with a direct, unbroken paternal line to such a historical person. If you can prove this, would be really something, IMO. If not, which is statistically more likely, you may still be a descendant or connected somehow and there are probably many interesting stories you can tell about the journey.